Distance 12 km/hr × (frac{1}{12}) hours 1 km

Thus, the length of the bridge is 1 kilometer.

Method 2: Using Speed in Different Units

The problem can also be solved by converting the given speed into a different unit, such as meters per second (m/s), and using the time in minutes. Here's the step-by-step solution:

Step 1: Convert the speed from km/hr to m/s.

Speed 15 km/hr 15 × (frac{1000}{3600}) m/s 4.16667 m/s

Step 2: Convert the time from minutes to seconds.

Time 5 minutes 5 × 60 300 seconds

Step 3: Calculate the distance covered using the speed and time in different units.

Distance Speed × Time 4.16667 m/s × 300 s 1250 meters

Therefore, the length of the bridge is 1250 meters.

Method 3: Using a Different Speed

Let's explore another problem with a different speed: the speed of the man is 15 km/hr, and he crosses the bridge in 5 minutes. We can solve this problem as follows:

Step 1: Calculate the distance covered in 60 minutes (1 hour) with the given speed.

Distance 15 km/hr × 1 hour 15000 meters

Step 2: Calculate the distance covered in 5 minutes.

Distance 15000 meters × (frac{5}{60}) 1250 meters

Thus, the length of the bridge is 1250 meters.

Conclusion

Using the basic distance formula and proper unit conversion, we can accurately determine the length of a bridge based on the speed and time taken to cross it. This is a useful problem-solving technique in various fields, including engineering, transportation planning, and physics.

Keywords: speed, time, distance, bridge length, conversion